I'm wondering if all the vari-target is doing is just advancing the score motor off the stuck position.

Rob, was the suspect 1C switch (inner most switch) labelled the motor return switch on the diagram inside the cabinet? I think this was the only Normally Open switch on the stack. Is this the motor home switch below? If so, could this be the problem below? ( from pinrepair.com)

The Score Motor's Home Switch.
Check the score motor's "home" switch (on Gottlieb's, usually at 1C or 4C). This switch is what turns off the score motor when it rotates to a "home" position every 120 degrees. Because of the score motor's electro-motive force (EMF) when the motor turns off, the score motor home switch gets a "blue arc" (easy to see when the score motor rotates!) every rotation of the score motor. The blue arc is *twice* the powering voltage due to the EMF that occurs as the magnetic field of the motor collapses when the power is removed. This blue arc makes the home switch wear and pit easily, and go out of adjustment. If the home switch is out of adjustment or worn, this too can allow the score motor to "over run" a home position, and perhap never stop running! Or on the other hand, when the score motor starts running due to another switch, the home switch may be so pitted and dirty it will not allow the motor to run to the next home position. This will often freeze the game and not allow it to play. Because of this it is absolutely necessary to make sure the home switch is clean and properly adjusted on any EM game.